title: Seasonal fluctuations in serum concentrations of vitamin D metabolites in normal subjects.
mesh_terms: D015652:25-Hydroxyvitamin D 2; D001800:Blood Specimen Collection / Q000379:methods; D004872:Ergocalciferols / Q000031:analogs & derivatives* / Q000097:blood; D006801:Humans; D012621:Seasons
chemical_list: D004872:Ergocalciferols; D015652:25-Hydroxyvitamin D 2